Examining the effect of interstitial space on Eastern oysters (Crassostrea virginica): applications of photogrammetry and three-dimensional modeling

Global oyster populations have decreased by as much as 99% in the past century. Oysters are known ecosystem engineers, providing benthic habitat for macrofauna, linking benthic and pelagic food webs, improving water quality, and mitigating shoreline erosion. Restoration efforts are critical in re-establishing native oyster populations. In the Chesapeake Bay, where oyster loss is primarily due to severe over harvest, artificial substrates with geometric shapes are widely used in restoration efforts. However, natural oyster reefs form emergent shapes with a high degree of aggregation and many interstitial spaces (three-dimensional volumetric spaces between oysters within a reef). The lack of interstitial space in artificial substrates contrasted with the presence of interstitial spaces in natural reefs led to the research question: Is there an amount of interstitial space which facilitates oyster recruitment and survival? Previous studies have hypothesized the importance of interstitial space in oyster reefs; however, current research lacks practical and effective methodology for measuring interstitial space of any ecosystem. We implemented a field study to observe the direct effect of interstitial space on oyster recruitment and survival using a concrete artificial oyster reef. Additionally, we used photogrammetry and three-dimensional digital modeling to develop a method for measuring interstitial space of the concrete artificial oyster reef used in the field. We found there to be significantly greater oyster recruitment and survival on substrates with 50 – 100 cm3 interstitial space per 50 mm2 surface area. This is the first study to directly examine the effect of interstitial space on oyster recruitment and survival. This is also the first study to develop a practical methodology for measuring interstitial space which may be transferred for use in other systems, as photogrammetry and three-dimensional modeling are not limited to oyster reef ecosystems. Filling these knowledge gaps will have positive impacts on oyster reef restoration and other ecosystems in which interstitial space is hypothesized to play a critical role